Large-scale synthesis of coaxial carbon nanotube/Ni(OH)(2) composites for asymmetric supercapacitor application

Coaxial carbon nanotube-nickel hydroxide (CNT/Ni(OH)(2)) composites are prepared by a simple, one step and inexpensive chemical coprecipitation method. The coaxial coating of nickel hydroxide provides a three dimensional (3D) structure for easy access of electrolyte. Asymmetric supercapacitors (ASCs) are fabricated using coaxial CNT/Ni(OH)(2) composites as positive electrode and reduced graphene oxide (rGO) as negative electrode. The operation voltage is expanded to 1.8 V in spite of the use of aqueous electrolyte, revealing a high energy density of 35 W.h kg(-1) at a power density of 1.8 kW.kg(-1). This strategy for choice of coaxial metal hydroxide CNT composites provides a promising route for next generation supercapacitors with high energy as well as power densities. (C) 2014 Elsevier Ltd. All rights reserved.